I got an $800 water bill the October my husband went into hospital. It turns out it was a hidden leak. That resulted in no water in the barn to this day, as I've never managed to get it fixed. And that was just for half a year. So I can sympathize with the huge bill! In years when I do have to water, even with the deep mulch, it can reach $500 for the half year.
But your garden is an oasis in a sea of yellow, for me that would be worth it.